I. Field
The present disclosure relates generally to electronics, and more specifically to a matching circuit.
II. Background
Amplifiers are commonly used in various electronic devices to provide signal amplification. Different types of amplifiers are available for different uses. For example, a wireless communication device such as a cellular phone may include a transmitter and a receiver for bi-directional communication. The transmitter may include a driver amplifier (DA) and a power amplifier (PA), the receiver may include a low noise amplifier (LNA), and the transmitter and receiver may include variable gain amplifiers (VGAs).
A transmitter may include a driver amplifier and a power amplifier coupled in series. The driver amplifier may have an output impedance of Z1. The power amplifier may have an input impedance of Z2, which may be different from Z1. An impedance matching circuit may be coupled between the driver amplifier and the power amplifier and may be used to match the Z1 impedance at the output of the driver amplifier to the Z2 impedance at the input of the power amplifier. It may be desirable to perform impedance matching in an effective manner so that high gain, high output power, and high power-added efficiency (PAE) can be obtained for the power amplifier.